It's a fact of London roads that pedestrians, cyclists and motorists all hate each other at times. And given the standards of cycling, driving and walking in the U.K. capital, there's good reason.

There's also good reason to think drivers could pave over these tensions just by thinking more about their wallets.

As a cycle commuter, I'm obliged to share a traffic lane with bus drivers, and know too well their penchant for what Americans call "jackrabbit starts" and "stopping on a dime."

Buses pull out of stops, accelerate to an Olympic sprint--overtaking my bike--and then jam on the brakes just in front of me at the next stop, throwing any standing passengers off balance. Sometimes they pull in before fully overtaking me, forcing me to jam on my brakes to avoid being pushed into the sidewalk. Usually, I'm able to then go around their outside, drawing level with the driver before the bus has come to a stop -- so they've gained nothing, and burned some brake and tire rubber in the process.

Rubber's not all they're burning: aggressive driving uses up fuel needlessly. Even if cycle safety weren't a concern (and it should be), the bus companies could save a penny or two on fuel by telling their drivers to observe the U.K. government's advice on fuel-efficient driving: "speed up and slow down smoothly."

The U.S. Department of Energy goes a step further and quantifies the costs of aggressive driving. Steep accelerations and braking can lower gas mileage -- the distance covered by a gallon of gas -- by 5 percent. Drive sensibly, and the equivalent gasoline savings amount to $0.19 per gallon, based on an assumed fuel price of $3.72 per gallon, the department says . (At highway speeds, the savings are greater -- 33 percent, or $1.23 per gallon.)

In the U.K., the price of diesel, the fuel used by more than 97 percent of London's 8,546 buses, averages 6.49 pounds a gallon ($10.25). (The capital also has about 200 hybrid buses and 5 hydrogen-fueled vehicles). With the average diesel bus covering 6.1 miles per gallon, and the fleet covering 486 million kilometers (302 million miles) a year, we can deduce that fuel use is about 49.5 million gallons.

The annual fuel bill for London buses therefor comes to about 321.3 million pounds. Save 5 percent of that, and you’re talking about 16 million pounds a year. And if you're cutting fuel consumption by 5 percent, it follows that you're cutting carbon dioxide emissions and particulate pollution by a similar amount. That can only be a good thing, given that London, the Olympic Games host city for 2012, last year exceeded annual European air pollution limits just four months into the year.

That's uncomfortable for all London cyclists -- but at least in the Olympic velodrome, there aren't any buses.